Advice please not sure what to think.

So I realized I accidently put this in the wrong topic I just signed up for this app so I don't even know how to delete it from the other one... So any ways my question is: So I was on the depo shot for six years, I stopped taking it may 1 of 2014 had my period in August 1 2014 it was really heavy and I do get heavy ones typically. (Have not had my period before that since before taking depo. ) I also got it again this year in April for 6 days didn't get any thing in May but I took ovualtion test and they came up positive but never became prego. This month just recently I spotted for not even a day and a half very lightly, looked it up and was described as possible implantation bleeding because periods are typically 3 or more days mine are usually six days. Could it still be the depo?? Or no.